Slightly Fancier

Even Fancier

Get the code with git. Use make to build the docs and do other stuff.
If you plan on hacking on npm, make link is your friend.

If you've got the npm source code, you can also semi-permanently set
arbitrary config keys using the ./configure --key=val ..., and then
run npm commands by doing node cli.js <cmd> <args>. (This is helpful
for testing, or running stuff without actually installing npm itself.)

Uninstalling npm does not remove configuration files by default. You
must remove them yourself manually if you want them gone. Note that
this means that future npm installs will not remember the settings that
you have chosen.